Commercial Refrigeration Certification Practice Test 2025 – Your All-in-One Guide to Success!

In systems where high pressure drops occur in the evaporator, using a thermal expansion valve (TEV) with an external equalizer is essential. An external equalizer allows for accurate pressure sensing of the evaporator outlet pressure, which is crucial in managing the refrigerant flow.

When an evaporator experiences a high-pressure drop, it can cause fluctuations in the pressure sensed within the evaporator, potentially leading to inadequate refrigerant flow and inefficient operation. The external equalizer pipe compensates for these changes, ensuring the TEV can respond appropriately to the actual cooling needs by maintaining consistent superheat levels. This results in stable operation and maximized cooling efficiency.

Using a standard TEV without an external equalizer in such scenarios may not correctly account for the pressure loss, leading to improper refrigerant flow and inefficient system performance. Therefore, the TEV with an external equalizer is the preferred choice for managing high pressure drops effectively.